This invention relates to cushioning devices, and more particularly to cushions having inflatable cells.
Those individuals who for one reason or another are confined to sitting or reclining positions for extended periods of time exhibit a tendency to develop decubitus ulcers, more commonly known as bed or pressure sores, and this of course is the result of inadequate blood circulation at the skin area where the body is supported. For example, the weight of a person sitting in a wheel chair is transferred primarily through the buttocks to the skeletal system, with most of the weight being concentrated at the bony prominances of the buttocks. It is in this region that the skin tissue is likely to break down and cause pressure sores.
Of course, the tendency for pressure sores to develop may be lessened considerably by distributing the weight of the body more uniformly over the supporting device on which the body rests, whether that device be a seat cushion or mattress, and to this end cellular cushions have been developed. These cushions have closely spaced flexible air cells which project from a common base through which their interiors are connected, so that the base serves as manifold. With only minimal inflation, the cells will support an individual, and indeed will spread out over the surface area of that portion of the body which sinks into the cushion so that the body weight distributes uniformly over the cushion. A cushion of the foregoing construction forms the subject of U.S. Pat. No. 4,541,136.
While cellular cushions have reduced the incidence of pressure sores, such cushions do on occasion present problems, most of which are peculiar to specific users. For example, some individuals have a tendency to slide forwardly on such cushions, while others have difficulty lifting either sideways or forwardly off of them. With still others, certain areas of their bodies are so sensitive that they should not be subjected to any forces or contact whatsoever, even a uniformly distributed force of the type provided by a cellular cushion. Some individuals have skeletal disfigurations or infirmities which are only aggravated by cushions of the conventional configuration and orientation. The foregoing problems exist irrespective of whether cellular cushions are used for supporting purposes, or merely as backrests.